1. Field of the Invention
This invention relates to a novel cushion, more particularly, to a sponge cushion for use as a mattress or a seat in a motor vehicle wherein the cushion is compressed about 65 percent in height by the weight of a person lying upon the pad.
2. Description of the Prior Art
In a sponge cushion for use as a mattress or a seat in a motor vehicle, heretofore, there has not been a sponge cushion considering the relation between the nature of the material thereof and the weight of a person lying upon the pad. Only a sponge cushion, which improved air circulation and provided a feeling of contact, has been used in replacement of a cotton cushion pad.
Ideally, a mattress cushion should, whether of cotton or sponge, possess characteristics wherein (a) when it is used, it will be able to deform so as to conform to an ideal lying position of a person, (b) it has a pleasant feeling upon skin contact, (c) it will not prevent the flow of blood in a body contact portion, (d) it is able to provide dispersion of water and heat emitted from a body lying upon the cushion, (e) it retains warmth very well, (f) a person lying upon the cushion does not feel contact with the floor lying under the cushion and (g) it has a good endurance.
The ideal lying position mentioned above means one similar to a position in which a person is standing naturally. The ideal lying position, as shown in FIG. 1 is arranged to extend horizontally from the center of the head (X) to the center of the sole of the foot (Y). This ideal lying position is in a form of an area of contact between the cushion and body at the back of the head, the back of the shoulder, the waist portion, the hip portion, an elbow, a thigh portion and the heel, and is in a form of a curve tying all of said points, in a plane of contact. This shape of the cushion does not prevent a flow of blood. Thus an ideal mattress cushion is one which may be deformed into the form of a said ideal curve when a downward force is exerted on the cushion by the weight of a person. The cushion, which may be deformed into the form of such a curve by the weight of a person results in no feeling of contact with the floor, good air circulation, a pleasant feeling of contact with the cushion and suitable warmth. When a person of a weight of 57 kg lies upon the mattress in a ideal lying position, the downward force is dispersed in the portions of the body as follows: in the back of the head 5 kg, the back of the shoulder 13.2 kg, elbows 2 kg.times.2=4 kg, the waist portion 5.7 kg, the hip portion 23 kg, thigh portions 4.8 kg.times.2=9.6 kg calves 4.6 kg.times.2=9.2 kg, heels 3.2 kg.times.2=6.4 kg.